NVIS Page 2

Copyright © 2002-2011 by Harold Melton, KV5R. All Rights Reserved. Feel Free to Link to This Page.

What is NVIS?

Near-Vertical Incident Skywave is a combination of radio hardware, skywave radio propagation, operating procedures, cooperation, and knowledge used by a group of radio operators who need reliable regional communications. It fills the gap between line-of-sight groundwave and long-distance “skip” skywave communications.

German ground forces first documented NVIS techniques in WW-II. NVIS was more fully documented, studied, and used by US forces in Vietnam. Radiomen in military vehicles discovered that their HF whips would sometimes work much better when tied down horizontally. Amateur radio operators have been studying NVIS propagation and operating techniques for at least fifteen years. In tactical military use, NVIS allows communications around the region while providing very little groundwave signal for the enemy to home in on. Any radio operator that has used a horizontal antenna well under a half-wave high has used NVIS.

NVIS propagation is generally considered to be F-layer ionospheric reflection at angles of 70-90 degrees. It is skywave propagation without the usual skip zone. The purpose of NVIS is to communicate locally and regionally, out to a few hundred miles, with moderate power, simple antennas, and no skip zone. NVIS is typically used on 160, 80/75, 60, and 40-meter bands by Amateur radio operators using relatively low horizontal wire dipole antennas.

NVIS operations are optimized by understanding and controlling two major factors: (1) Proper antenna design and placement, and (2) proper training of the operators. The antenna is designed and placed to provide the maximum possible gain straight up, on two or three frequency bands. Operator training includes an understanding of antennas, ionospheric propagation, and operational procedures.


3 thoughts on “NVIS Page 2
  1. I would greatly appreciate receiving any info regarding “German ground forces first documented NVIS techniques in WW-II”. I have not found any DOCUMENTED evidence that they used NVIS. Their knowledge of HF propagation at that time was second to none but
    where are the official reports ??
    From my findings most of the Internet references of Wehrmacht NVIS are based on the articles by Lt.Col.Fiedler.
    Thank you
    Aryeh 4Z5DF

    • Sorry, I don’t remember where that reference came from. It was like 13 years ago I wrote that article, and I took my info from ARRL Antenna Handbook, Army FM-24-18, and several web articles as listed on page 8 of this article.

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